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Dalton’s model
The last of Dalton’s Atom Model were at the time considered true for all reactions involving atoms the atom can be divided into even smaller particles and we have even discovered the actual internal atom structure, even able to view it through modern technology -
John Dalton 1803
Dalton was the first to prepare a table of relative atomic weights.
This theorythat Dalton first advanced in 1803, is the cornerstone of modern physical science. Dalton's atomic theory constists on :
1.All matter consists of tiny particles
2.Atoms are indestructible and unchangeable
3.Elements are characterized by the mass of there atoms
4.When Elements react, their atoms combine in simple, whole-number ratios -
William Crookes 1879
He did some work with "Cathode Rays" Later investigation of cathode rays by other researchers which led to the discovery of electrons.
He also isolated several elements for the first time, Thallium and Protactinium, are some of them, and he made observations about the radioactive decay of Protactinium -
J. J. Thomson’s Model (Plum Pudding Atomic Model)
this model, the atom is composed of electrons surrounded by a soup of positive charge to balance the electrons' negative charges, like negatively charged "plums" surrounded by positively charged "pudding". -
Ernest Rutherford 1900
Rutherford devised an experiment where alpha particles were fired at a very thin sheet of gold leaf.
That experiment showed that something dense and positively charged existed in the atom called the nucleus
He also proved that most of the atom was made of empty space. -
Rutherford Model
alpha particles could be deflected backwards was if most of the mass in an atom was concentrated in a nucleus.
To prove it he made the model of the atom which put all the protons in the nucleus and the electrons orbited around the nucleus like planets around the sun. -
Quantum Mechanical Model
The quantum mechanical model of the atom uses complex shapes of orbitals (sometimes called electron clouds), volumes of space in which there is likely to be an electron -
James Chadwick 1932
He contributed to atomic theory by his experiments proving the existence of neutrons.
He won the Nobel Prize in 1935 for his discover -
Niels Bohr 1963
Niels Bohr contributed the quantum theory of atomic structure
That theory states that an atom emits electromagnetic radiation only when an electron changes from one energy level to another, which changes our understanding of atomic "shells" to think of them more as energy levels that are to some extent inter-navigable by the electrons -
Bohr Model
The Bohr model is used to account for the spectrum of the hydrogen atom, but the basic idea is the same for all elements.
The single electron in hydrogen revolves around the nucleus in one of a limited number of circular orbits. When it is in the orbit closest to the nucleus it is in its ground state, this electron is in the valence band of the element. -
JJ Thomson 1987
He identified that electrons inside an atom could show, in other words, that they are visible
He stated that electrons were positioned by electrostatic forces.
Thomson had started to discover atomic theory that gives explains the atomic structure.
According to Thomson protons are embed in the atoms and electrons are present in atoms to make the atom electrically neutral
